• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.12
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• pp.98-103
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• 2019

With the increasing need for environmental protection, it is particularly important to improve the energy saving and reliability of refrigerators. Generally, the cold air flowing into the freezer compartment transits to the bottom of the refrigerating compartment, which can lead to uneven temperature distribution. This paper proposes two design solutions for improving the temperature distribution problem. Of these, the optimal refrigeration design was selected and tested using Computational Fluid Dynamics (CFD) modeling and simulation. The results showed improved uniformity of the temperature distribution inside the refrigerator, thus benefitting food storage while reducing energy consumption.

• Korean journal of food and cookery science
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• v.10 no.4
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• pp.405-411
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• 1994

This study was conducted to know the quality of chou made with flour pastes which were stored at different conditions of quick freezing, slow freezing, cold and room temperature. Also, this study included investigation of the chou properties such as expansion, sensory evaluation, degree of gelatinization, and physical and structural properties of paste were observed. There were not significant differences m diameter, height, volume, appearance, hollow formation, and sensory evaluation between the chou made with the paste stored at freezing condition and chou directly baked after pasting. Quick and slow freezing storages did not significantly affect the properties of chou, and the same results were obtained among the chou made with pastes thawed at room temperature and in microwave ovenrange. The chou of pastes stored at room temperature and in microwave ovenrange. The chou of pastes stored at room temperature and stored in refrigerator showed lowed expansion and value of sensory evaluation than those of frozen pastes. The paste stored at room temperature had the lowest hardness and viscosity compared with the other storage conditions. According to the observation of light microscope. the lipid bodies of the paste of freezing storage smaller those of the room temperature and refrigerator storage. The expantion of chou made with paste stored at room temperature was greatly decreased due to the high coalescence of lipid bodies, and also the paste components such as lipid, starch granule gluten at room temperature had inferior dispersion condition. The general tendency of the degree of gelatinization of chou were low in all treatments of paste. The values were 23.5%~46.0% in freezing, 77.3% in room temperature, 68.7% in directly baked after pasting, and 61.0% in cold storage, respectively. The formation and the taste of chou made with frozen paste were similar to those of chou directly baked pasting.

• Tunnel and Underground Space
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• v.15 no.3 s.56
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• pp.169-176
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• 2005

The decreasing pattern of underground temperature measured at 'Gonjiam cold storage cavern' during 7 years which was the first commercial scale underground food storage cavern in Korea was analyzed. The variation of energy consumption was discussed by comparing the consumed energy at the initial operation stage with that at later stage, when the temperature distribution reached a stabilized condition. The point to be considered at the design stage was also discussed by comparing the required refrigerator capacity at the initial operation stage with that at later stage. The extra energy to freeze the groundwater contained in pore space was discussed by analyzing the changing pattern of the rock temperature. The variation of measured rock temperature was compared with the estimated temperature using a numerical code, FLAC. The accuracy of the numerical estimation was discussed by comparing the heat flux measured by the operation time of the refrigerator with that estimated numerically.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.8
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• pp.1116-1122
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• 2009

As a result of this study, we reached the following conclusions. With appropriate setting of oil pressure and flow rate, it operated same rotation speed with existing cooler by electrical transmission. In initial operation, a temperature of a cold storage is lower rapidly. As an internal temperature of a cold storage is lower, a decreasing rate of temperature is lower. As a result of comparing the both type, the cooler of oil pressure type showed the following results. The decreasing rate of temperature was more faster and shorter operating time was more shorter than existing cooler of electric type. The actual case of a cold storage, the cooler of oil pressure type can prevent quality deterioration and decrease power consumption. As an internal temperature of a cold storage is lower, power consumption increased rapidly, the oil pressure type showed lower power consumption. COP of two of these types decreased continuously as the internal temperature of a cold storage being reach setting temperature, and that of oil pressure type showed higher amount about 25%. As a setting temperature is lower, the number of refrigerator's operating times are less and operating time is longer, so power consumption is increased in the maintenance of a cold storage's internal temperature, power consumption of hydraulic type showed lower amount about 21~25% in two of these types.

• Animal Bioscience
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• v.37 no.2
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• pp.210-217
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• 2024

Objective: This study investigated the efficacy of different concentrations of gelatin supplementation in long-term semen extender on boar semen quality during storage for 10 days at 17℃. Additionally, oxytocin was added to stored semen to enhance fertility. Methods: In Experiment 1, boar semen was collected, diluted with gelatin at concentrations between 0% and 2.5% (w/v) and mixed with a semen extender. Then, it was kept in a refrigerator at 17℃ and stored for 10 days. In Experiment 2, the sperm quality was examined after adding 0, 5, and 10 IU oxytocin per artificial insemination dose to the most effective semen extender from Experiment 1 and placing it in a refrigerator at 17℃ for 10 days. In Experiment 3, the fertility potential in terms of non-return rate and litter size was determined using the most effective solid-stored semen supplemented with oxytocin. Results: The results indicated that sperm quality decreased with increasing storage time (p<0.05). The sperm quality in terms of total motility, progressive motility, and viable sperm with intact acrosomes and high mitochondrial potential was the highest with 1.5% gelatin supplementation (p<0.001) on all days of storage. Treatment with oxytocin did not affect sperm quality (p>0.05). The non-return rate and litter size after insemination with semen supplemented with 1.5% gelatin and 10 IU of oxytocin after 8 to 10 days of storage were comparable to those of the control group (p>0.05). Conclusion: A semen extender as a solid medium supplemented with 1.5% gelatin successfully preserved boar semen for a long storage duration. Treatment with oxytocin did not affect sperm quality. In addition, the fertility capacity using 1.5% gelatin with 10 IU oxytocin and stored for 8 to 10 days was acceptable and comparable to that of short-term storage.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.4
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• pp.464-471
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• 1999

This paper describes a design of the helium-recondensing system utilizing cascade Roebuck refrigerators. Superconducting generator or motor has the superconducting field winding in its rotor that should be continuously cooled by cryogen. Since liquid helium transfer from the stationary system to the rotor is problematic, cumbersome, and inefficient, the novel concept of a rotating helium-recondensing system is contrived. The vaporized cold helium inside the rotor is isothermally compressed by centrifugal force and expanded sequentially in cascade refrigerators until the helium is recondensed at 4.2K. There is no helium coupling between the rotor and the stationary liquid helium storage. Thermodynamic analysis of the cascade refrigeration system is performed to determine the key design parameters. The loss mechanisms are also explained to identify entropy generation that degrades the performance of the system.

• Food Science and Preservation
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• v.14 no.2
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• pp.113-118
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• 2007

A LED (light emitting diode) was attached inside the cold $(4^{\circ}C)$ compartment of a home refrigerator to investigate a possible effect on freshness prolongation of cabbage over 10 d of storage. The LED increased chlorophyll synthesis, inhibited vitamin C degradation and increased the content of phenolics, compared to values measured in cabbages stored in an identical refrigerator without the LED. In the refrigerator with the LED, the color of cabbage leaves remained green for a period fourfold longer than that seen in a conventional refrigerator. Vitamin C content was twice that of a conventionally stored cabbage, and phenolic consent was 14% higher in the LED-illuminated vegetables.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.250-255
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• 2003

TMA clathrate that is used as PCM of low temperature thermal storage system in this research creates hydrate crystallization at higher temperature then pure water, and its application is expected as PCM because of comparatively big latent heat without phase separation phenomenon. Acetone, Ethylen Glycol, and Ethanol is used as additive and evaluated experimentally for the purpose of the improvement in subcooling of TMA clathrate. In view of the results so far achieved subcooling is improved, the running time of the refrigerator is reduced. Thus the results are expected to use for the increase of coefficient of performance of low temperature thermal storage system in the building.

• Korean Journal of Food Science and Technology
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• v.11 no.2
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• pp.131-137
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• 1979

The effect of CA storage on the fresh ginseng roots were investigated. The quality of red ginseng prepared from the roots of CA storages were also evaluated and following results were abtained. 1. Fresh ginseng roots stored at controlled atmosphere showed normal appearances for as long as 6 months, while they were contaminated with fungi in 3 months when stored in the refrigerator. 2. The weights of fresh ginseng roots were reduced for 180 days to 9% and $4{\sim}5%$ in cold storage and CA storage, respectively. Those of CA storage were higher than cold storage in their hardness. 3. Bitterness of the fresh ginseng root was generally decreased as it was stored long. The decrease in bitterness of CA group was less than cold-storage group. 4. Respiration of CA group was lower than that of cold-storage group for whole storage periods. 5. Red ginseng perpared from the fresh roots stored for 180 days was incomplete in gelation and its husk was easily detached. 6. Total saponins of the red ginseng made from the fresh ginseng of CA storage was greatly reduced as compared to that prepared commonly.

• Korean Journal of Food Science and Technology
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• v.26 no.3
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• pp.199-203
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• 1994

Software for refrigerator capable of both rapid fermentation and suitable storage of Kimchi was developed and its performance was investigated. Refrigerator system consists of an insulated fermentation room, heater, damper for the control of outer cold air and two sensors for recognizing temperature of heater and fermentation room, which control temperature and time period of affecting Kimchi fermentation. Effects of fermentation at different NaCl concentration and three fermentation function keys were studied; At key I, time which was elapsed to edible ripening state, pH 4.5 and total acid 0.6%, was about $3{\sim}4$, $4{\sim}5$ and $11{\sim}12$ days, respectively. At key II, time was about $2{\sim}3$, $3{\sim}4$, and $10{\sim}11$ days, and at key III, about 2, 3 and $9{\sim}10$ days, respectively. Effect of storage at three fermentation function keys was all maintained to the level of a palatable pH range until 14 days. Sensory evaluation of Kimchi showed also significant difference in a taste.